| Nowadays the construction of an ideal scaffold with three dimensional structure was one of the key factors whether biomaterials can be successfully developed. The biomaterial scaffold can supply adherent carrier for cell growth. It can promote cell growth, and finally form special functional and morphologic tissue or organ. Therefore, it was the core research to find the extracellular matrix materials that have developed tissue regeneration potential. Collagen possessed the good biological and chemical characteristics, The source of collagen was wide. Collagen had low antigenicity, good biological compatibility and degradation, then decomposed into small molecules and short peptides that was beneficial to body absorption after some time. The dissolubility of collagen was good, and functional group was modified easily. When collagen was displayed with other biological active constituent, it had synergistic effect so that cell can easily proliferate on the surface of collagen. As the use of biology and clinic for many years, people found the deficiency of collagen as biological scaffold materials. This deficiency restricted seriously development of collagen with good characteristics. People found that collagen wasn't satisfied for mechanical environment of body organ as its low mechanical strength. The collagen wasn't easily be fixed and the rate of biological degradation was too rapid to control. All of those were related with relatively low molecular weight and diameter of particle. With the summary on all kinds of physical and chemical method in the modification of collagen before, in this paper, a new-style crosslinking agent ,γ-thiobutyrolactone, used in modification of natural collagen was adopted. Fresh pigskin as the raw material, collagen extracted by hay bacillus neutral protease A.S1.398 two-step (inhibition of protease activity)heat dissolving technics was modified by the crosslinking agent. The influencing factors on physical and chemical character of collagen, different acid environment, different pH adjusted by different amount of imidazole, and different modification temperature were studied. At the same time, molecular weight of collagen, diameter and distribution of particles, exterior of protein fiber, composition variation of amino acid and token of heat mechanical property of collagen, surface hydrophilic property of protein membrane material, and spinnability of modified protein were studied. The experimental results showed that the collagen protein can be modified obviously with this crosslinking method. The mean molecular weight and highest molecular raise 2.3 times and 1.7 times, and almost half of protein were attributed to high molecular weights that present asynechia distribution, and was contributed to enhancement of mechanical property of collagen. Accordingly, as the collagen laterally crosslinked and linearized, diameter and exterior of particles changed obviously. Good hydrophilic property of protein membrane material was not varied, and the rate of breaking elongation was increased evidently. The experiment data showed that crosslink action was able to generate in acetic acid solution rather than in lactic acid solution. In the range of neutral pH, the effect of the imidazole amount on the modification of collagen was most remarkable, reversely, the effect of temperature was little. In this paper, the synthesis of γ-mercaptobutyrolactone, the crosslinking agent, was carried out. And then it was in agreement with the standard in the comparison between the IR spectrum and contact angle experiments. Spinning experiment was also carried out elementarily. It showed that the modified protein processed partly spinning property that collagen wasn't provided with before. But the extent of modification was limited, it need further study.
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